Telephone



(NoModelJ 7 T. A. EDISON.

TELEPHONE. No. 257,677. Patented May 9, 1882.

UNITED STATES PATENT OFFICE.

THOMAS A. EDISON, OF MENLO PARK, NEW JERSEY.

TELEPHONE.

SPECIFICATION formingpart of Letters PatentNo. 257,677, dated May 9,1882.

Application filed October 17, 1881. (No model.) Patented in England Tune15, 1878.

T 0 all whom it may concern (Case No. 158 13,) of which the following isa specification.

This application is a division'ot my application No. 158, filed November11, 1878, and the said division is made for the purpose of separatingfrom said original application matters that are not in interference, andfor separating the different features of invention into two additionalapplications. The present I term Case No. 158 13.

Letters Patent in Great Britain No. 2,396 show the present devices. Saidpatent was applied-for June 15, 1878, but the specification was notfiled until December 13, 1878.

This portion of my invention relates to the telephone-instrumentrepresented in them:- companying drawings, Figure] being a sectionalview and Fig. 2 a section at right angles to Fig. 1.

The transmittirig-instrument to which this portion of my inventionrelates is intended to transmit oral communications over electriccircuits.

In my original application No. 158 I have shown a receiving-instrumentand electric circuits; but as this transmitter may be used with anysuitable circuits or receiving-instrument, these parts do not form anecessary feature of this division of my said application.

In my application No. 130, filed April 27,

1877, the diaphragin' is in direct contact with;

a surface of plumbago or similar material.

In my Patent No. 203,015 a tension-regulator is described, composed offiber and an electric conducting material-such as plumbago.

In my Patent N 0. 203,016 I have described a button of lainp-blackforming thetensionregulator, and there isa metallic plate interveningand in contact with both the carbon and the diaphragm.

The peculiar features of the present invention as distinguished from.the aforesaid devices relate to a telephonic diaphragm that is notclamped at its edges, but rests at one side against a support, and it isheld in place by a,

yielding pressure applied to the other surface, and the tensionregulating device is applied between the diaphragm and the support, sothat the pressure upon the tension-regulator will be varied by thevibrations of the diaphragm as acted upon by articulate speech or othersounds, and the electric condition of the line .will be varied, so thatthe current will undusuch disks, and the plate d is at the oppositesides of these disks 0, and it is sustained in place by suitable means.I have shown a bracket, (1, connected to a base. 0, which is fastened tothe mouth-piece b. The spring 6 serves to press the plate or diaphragm 6toward the tension-regulator, so as to apply the proper initialpressure. One conductor is connected with the back plate, cl, and theother to the spring 6 or diaphragm 6. The soundwaves act against theplate or diaphragm 6 and vibrate the same, and the resistance in theelectric circuit is varied according to the action ot'thc vibratingdiaphragm on the tension regulator. The edges of the diaphragm -or plate6 are preferably corrugated or turned over behind the back edges of themouth-piece, as represented. This stift'ens the edges of the diaphragmand prevents any independent or false vibrations at said edges.

I claim as my invention- 1. A tension-regulating device, a support forthe same, a diaphragm resting against the tension-regulator, and aspring-prcsser acting to retain the diaphragm in place, substantially asspecified.

2. In a telephone a diaphragm, the whole of which is free to vibrateunder the action of sound, a tension-regulating device at one side ofthe diaphragm, a mouth-piece, and a spring acting to press the diaphragmtoward the tension-regulator, substantially as set forth.

3. In a telephone-instrumcut, a diaphragm that is corru gated or ribbedat or near its edges, substantially as set forth.

4-. In a telephone, the combination, with the diaphragm, of a yieldingtension-regulator at one side and a yielding presser acting against theother side.

Signed by me this 7th day of September, A. D. 1881..

Witnesses: THOMAS A. EDISON.

GEo. T. PINCKNEY,

HAROLD SERRELL.

